Stem Cells May Help to Create Human Liver

A new study shows that it may actually be possible to create a liver from stem cells.

According to Japanese researchers Takanori Takebe, MD, and Hideki Taniguchi, MD, of Yaokohama City University in Japan, they created human liver buds complete with blood vessels that can perform metabolic activities when implanted in mice.

Researchers hope these could be used in humans, as well. However, they note that study results show the need for further research before this can be determined. In fact, Takebe said, according to Med Page Today, that it would probably be necessary to implant "tens of thousands of liver buds" to generate a functioning liver in a single human adult. Doing this could take anywhere from 5 to 7 years.

Takebe and colleagues used human somatic cell-derived iPSCs to develop into hepatic endoderm cells--a type of progenitor cell destined to mature into normal liver cells--and then co-cultured these cells with human umbilical vein endothelial cells and human mesenchymal stem cells.

They believed this approach could help "recapitulate" the process by which real human livers develop during the early fetal stage. Researchers said that as they observed the liver buds successfully forming in culture, they were transplanted in mice by cutting a window in their skulls and placing the liver buds on their brains.

Study results show that the liver buds' vessels made connections with the animals' cranial vessels, at which point the buds further matured into tissues that strongly resembled the adult human liver. Takebe and colleagues confirmed that these mini-organs carried out metablolic functions expected in the liver and even expressed normal liver proteins such as albumin and alpha-1-antitrpsin. The study results also show that the transplants were metabolically active enough that they improved survival in some of the mice with drug-induced liver failure, compared to those that received sham surgery.

More information regarding the study can be found online in the journal Nature.